03 Silverado 1500 5.3L AC System

[Summajet]

I am needing to replace the Ac compressor on my truck due to a bad intermittent ac clutch relay. I am trying to confirm the correct p-nut fitting?

I looked at rock auto and it has either a 12 or 3 position for the p-nut fitting.

Is the p-nut fitting where the pressure line connects to the Accumulator-drier receiver?

Thanks,

 

[Summajet]

Picture

I am needing to replace the Ac compressor on my truck due to a bad intermittent ac clutch relay. I am trying to confirm the correct p-nut fitting?

I looked at rock auto and it has either a 12 or 3 position for the p-nut fitting.

Is the p-nut fitting where the pressure line connects to the Accumulator-drier receiver?

Thanks,

 

[rockola1971]

I am needing to replace the Ac compressor on my truck due to a bad intermittent ac clutch relay. I am trying to confirm the correct p-nut fitting?

I looked at rock auto and it has either a 12 or 3 position for the p-nut fitting.

Is the p-nut fitting where the pressure line connects to the Accumulator-drier receiver?

Thanks,

Huh? The clutch relay is not on the Compressor so why would you need to replace the compressor?

 

[OR VietVet]

Did you have a shop look at it and this is what they told you and now you are planning on doing the compressor yourself?

Here is the compressor: https://www.rockauto.com/en/moreinfo.php?pk=452336&cc=1412086&pt=6628&jsn=928

Here is the accumulator: https://www.rockauto.com/en/moreinfo.php?pk=436627&cc=1412086&pt=6972&jsn=935

Here is the orifice: https://www.rockauto.com/en/moreinfo.php?pk=13085953&cc=1412086&pt=6936&jsn=945

Here is the clutch cycling/low pressure switch: https://www.rockauto.com/en/moreinfo.php?pk=436618&cc=1412086&pt=4284&jsn=1022

Get flush fluid and a way to flush the system.

Almost forgot: Get a new relay, BUT I would like to hear the details about the diagnostics on the problem.

 

[Summajet]

Here is what has been happening.
Intermittently the Ac will engage when pushing the ac button. Some times not. I had the shop check pressures, recover the freon and then they pulled a vacuum on the system and it help with no leaks for an hour. Then refilled to the 1.6lbs per the refrigerant label under the hood. I went back to the shop and explained when engaging the ac button the ac does not cycle on. It is fully charged and the pressures are within specs. I asked the mechanic and the next time it happened i stopped at the shop. With the ac button engaged at the heater controller the ac clutch did not engage. The mechanic took a hammer and tapped the bottom of the ac compressor and as he did the ac clutch engaged and ran cooling down the inside of truck. Am i missing something they should have checked? He said the ac low pressure switch is fine.

He told me that the relay/magnet in the clutch can get weak over time and when tapping compressor housing with a hammer if it engages more than likely the relay is weak in the compressor. I explained early in the morning before it gets hot the ac works. After 3pm in the evenings it will not engage. Once last week i could not get it to engage. Then i used a hammer and tapped the compressor case and it work.

One other thing is that when they fully charged the ac it would not get cooler than 62 degrees and the ambient temperature was 89 outside.

I was going to replace the compressor, accumulator, orifice tube, and condenser and ensure i can get the best cooling out of the system.
I had replaced a compressor and accumulator on my 03 yukon a few years ago.

I appreciate any help you can offer.
Thanks